Field of the Invention
The present invention relates to a rotary handle for a thermostatically controlled mixing valve.
Description of the Background Art
In thermostatically controlled mixing valves for plumbing fixtures with temperature sensors/valve elements in the form of expanding-material elements, the relation between the rotation angle of the rotary handle, with which the temperature is selected and adjusted, and the path of the valve element is substantially linear. This means that the path of the valve element per step angle of the rotary handle in a low-temperature range below 25° C., in a mid-temperature range of from 25 to 40° C., and a high-temperature range above 40° C. is substantially uniform.
In plumbing fixtures with thermostats, however, it is expected that fine adjustment of the water quantity is possible specifically in the middle temperature range. For this reason, expanding-material elements having special characteristic curves are selected for temperature sensors. Expanding-material elements with moderately steep characteristic curves assure a fine temperature regulation, but require an especially large rotation range for the rotary handle. This occurs, however, at the expense of the adjustable/selectable cold- or warm-water flow temperatures, because the rotation angle of the rotary handle is restricted by the required fixed stops.
Known from the conventional art, for example, from European Pat. Appl. No. EP 1 150 054 B1, are actuation mechanisms, in which the attempt is made to produce characteristic curves with different slopes in the low- and high-temperature range compared with the medium-temperature range. The characteristic curve of the valve element is influenced by different pretensioned springs, so that its slope in the medium-temperature range is flatter than in the other temperature ranges. Therefore, in the medium-temperature range a broader rotation range should be achieved, without increasing the entire rotation range of a temperature selection handle.